The actress Song Yun-a is as frank and open as her smile. “Do you remember that my name was always billed after my male partners in my previous films? They said Shin Hyun-jun and Song Yun-a in ‘Face,’Seol Kyung-gu and Song Yun-a in ‘Lost In Love’ and Park Joong-hoon and Song Yun-a in ‘A Masterpiece in My Life,’ something like that.” But her latest horror movie “Arang,” which was recently released, gives her first billing for the first time. She plays a detective opposite the younger actor Lee Dong-wook in the movie. “I felt responsible for my name for the first time,” Song says.

On MBC’s new drama “Elder Sister,” which started airing Saturday, she plays the title role, a 26-year-old art student growing up in a rich family who must suddenly take on the responsibility of head of the family and take care of her brothers after their father goes bankrupt and then missing.

“I was burned out and wanted to take a rest after filming two movies and drama back to back from the beginning of last year,” Song says. But she changed her plans when she heard that the writer of the new drama is Kim Jung-soo, who also wrote hit dramas “You and Me” and “Lifetime in the Country.” “I have wanted to work with Kim, who writes warm stories about ordinary people’s lives,” she explains. Her new image as a decent, gentle and docile woman is a far cry from the bad girl image she projected when she started out in the late 1990s. In the mega-hit drama “Mr. Q,” which got more than 60 percent viewer ratings, she appeared as the head of the design department in an underwear company who bullied the female lead Kim Hee-seon. “I played the typical bad girl in a trendy soap opera,” she said.

Although now one of Korea’s leading actresses, Song spent four years as an unknown.

Song debuted at the recommendation of a senior in a modeling agency while she was a freshman studying Cultural Anthropology at Hanyang University. She made advertisements for magazines and was an extra in TV shows. “Everything happened quite suddenly. I didn’t think of becoming an actress in detail,” she says. In her middle and high school days, she watched TV soaps on the sly, putting a wet towel on the TV to reduce the heat so her father, who banned her from watching, wouldn’t know. Until a few years ago, her father would call her to make sure she came home at 10 p.m.

“My cell phone is silent these days even when I come home late. I feel sad to think that my father is too old to nag me,” she says ruefully. Asked if her father hopes she is seeing a man when she is out late, the actress looks at the reporter out of the corner of her eye. “Possibly,” she says. “But the problem is I’m not in a hurry to get married.”